1. Field of the Invention
The present invention is directed to a wind power turbine for industrial and home/farm uses with enhanced stability and efficiency. In particular, it deals with a compact wind power turbine with a stationary, frontward pointing nose, isolated from the rotors, and tips for the rotors to capture ‘runoff’ fluid in operation to provide extra force to the rotors.
2. Prior Art Statement
In a world searching for energy, wind power is a perfect solution. Wind is a renewable source that is environmentally friendly and void of any harmful waste products. It is easily converted into electricity and is available in most parts of the world. Renewable energy is a major issue to which the world is turning, because of two major factors. These are: a desire to produce electric power at lower cost; and to produce it, preferably, with ‘zero’ pollution.
For many years there has also been an interest to reduce America's and the world's dependence on oil or other fossil fuels for power. Electricity from wind turbines is rising here in the United States and elsewhere often in groups dubbed ‘wind farms’, usually placed somewhat remotely to civilization, i.e. from where the produced electricity is used.
A wind turbine is a mechanical device that captures the wind's energy and coverts it to electricity. Much attention has been given to improve the efficiency and to lower the cost. Naturally these goals are often in opposition to each other.
There are two main basic types of wind turbines, horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). HAWT are the primary design for most power generation applications. The deficiencies and advantages of each design differ quite greatly. The present invention is a horizontal-axis wind turbine and thus prior art for HAWT products and designs is most pertinent.
Numerous inventors have proposed improvements for wind turbines or components. Representative ones related generally to the present invention are described below, and compared to problems remaining to be solved.
In U.S. Pat. No. 4,150,301, Bergey, Jr. describes a wind turbine which is self-governing at relatively high fluid velocities. Two sets of turbine blades are used to accomplish this aim. One set has a positive efficiency and the other has a negative efficiency at velocities where self-governing is desired. This system is quite complex and by design loses efficiency as wind speeds grow.
In U.S. Pat. No. 4,021,135, Pedersen et al., a modified wind turbine including a reaction type turbine wheel to more efficiently derive power from the wind stream is described; as well as an augmenter to increase the pressure differential across the turbine by producing a vortex downstream from the turbine. The design includes multiple sectors and rotors vying for wind force as well as complex wiring and designs. Such complexity leads to added costs, and also increases the number and type of failure modes.
Some early discussions on optimum rotor blades for power production included a patent by Baskin et al. (U.S. Pat. No. 4,557,666). The essential design here is commonly used in the large wind farms dotting America, especially those in the Mountain passes in California. It uses large rotors ca. 300 feet diameter and blades having fixed pitch in mid and tip sections. These ultra large are the apparent primary interest in wind power turbine design progress. Many of the problems and limitations of this design are related to the massive size of the towers and blades and provide little or no guidance for compact turbines for industrial or commercial sites as intended with the present invention.
More recently, Stiesdal et al. in U.S. Pat. No. 7,059,833 describes gains to be had by modifying the trailing edge design of rotors, at least over a portion of the blade, by attaching serrated trailing edges to the normal trailing edge of standard wind turbine rotors. In contrast to noise abatement attachments to the trailing edge near the rotor tip, Stiesdal et al. promote a much longer section with blunter angles on the serrations. This patent describes improving efficiency by modifying trailing edges on large, long rotor blades. The specifics presented are for a 62 m (192 foot) diameter rotor. It does not deal with the problem of wind rolling off rotor tips nor effects around the central hub of the turbine.
Wobben, in U.S. Pat. No. 7,540,716, provides improved rotor blades by aerodynamic consideration of the leading and trailing edges of the rotor and special attention to rotor tips. The main point is to have the tip of the rotor curved back towards the trailing edge of the blade. Spill off the end of the rotor tip is thus encouraged.
Small compact wind power turbines are considered in U.S. Pat. No. 7,214,029 by D. Richter. Nose design is discussed, but in the context of a streamlined body with a rounded nose and one or more rotor sets contained within the streamlined body. This type of turbine is indeed small, compact but more resembles the structure of a jet engine than the more typical wind power turbine developed to handle ambient winds on various sites. Richter deals primarily with laminar flow problems and enhancing power from such enclosed rotor systems. The design of nose and tail sections for enhanced power generation provide little guidance for exposed rotor wind turbines and the nose design in particular is in opposition to the problem with exposed rotor systems.
What is still needed is a cost effective, efficient solution for compact wind power turbines as are useful for specific site industrial, commercial or home installations. Areas in the center and at the edges of the turbine rotors could especially benefit from new designs presented in the present invention.